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Industrial applications require parts of components with specific surface properties such are good corrosion resistance, wear resistance and hardness. Alloys with those properties are usually very expensive and there is a great interest in reducing the cost of components for fulfilling these requirements. In this sense, laser surface processing has been used as a cost-effective technique to improve the surface properties of materials, by use of the laser beam heat for modification of its structure and physical characteristics. Laser surface treatments can be divided into direct processes, which only need the generated heat, such are hardening and melting, and processes which need filler material as alloying and cladding. Therefore, the aim of this paper is to summarize the results of several works based on laser surface treatments, in particular, hardening and melting of hot and cold work steels, and laser cladding of forming tools with nanoparticles. The microstructural characterization and mechanical properties (microhardness, wear resistance) will be described in each case.

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-In many applications in industry, securely attaching fiber optic sensors to metallic structures is important for optimum monitoring, overcoming the limitations of glues and adhesives which are known to degrade under certain circumstances. To avoid that problem, creating a metallic bond to attach the sensors securely to the metal surface is important. Commercial fiber optics with metal coatings can be used but it is important not to damage the sensor itself which is written in the thin optical fiber. In this work, an alternative laser cladding technology has been studied for embedding metal coated fiber optics into which Fiber Bragg Grating (FBG) sensors have been written. A three-step strategy was selected for embedding the metal coating fibers to create the best conditions to allow high quality measurements to be made. This has been seen to allow good control of the embedding process to be achieved and to minimize the thermal and mechanical stress generated. The research undetaken has shown that it is possible to embed Cu and Ni coated fiber optics containing sensors to over 300µm with low losses, of between 0-1.5 dB (or 0-30%) and yet still enable satisfactory strain and temperature measurement results to be obtained. The research has shown that both Ni and Cu coated FBG-based fiber optic sensors could be embedded successfully and shown to give good mechanical and thermal response to similar non-embedded sensors and give excellent crosscomparison with the conventional gauge used for calibration. The results are therefore particularly encouraging for the use of sensors of this type when incorporated to create metallic 'smart structures' achieving durability of the sensors through the use of this innovative technique. Permanent repository link

A high power diode laser has been used for surface melting of a 7075-T6 aluminium alloy in order to induce changes in the microstructure, which could lead to an improvement of its corrosion performance. The treatment produces a fine dendritic microstructure region at the surface, whose depth depends mostly on the temperature at the surface of the material and, only marginally, on the scanning speed of the laser beam. An analysis of the microstructure and second phases before and after the surface treatment is presented in this paper.